Detection of CH3+ in the O-rich Planetary Nebula NGC 6302
Journal article, 2025
Planetary nebulae are sites where ejected stellar material evolves into complex molecules, but the precise physical conditions and chemical routes that govern these processes are unclear. The presence of abundant carbon-rich molecules in O-rich environments poses particular challenges. Here we report the first detection of methyl cation (CH3+) in any planetary nebula, observed in the O-rich nebula NGC 6302 using JWST MIRI/Medium Resolution Spectrometer observations. CH3+ is a key driver of organic chemistry in UV-irradiated environments. Spatially resolved observations reveal that CH3+ is colocated with (CO)-C-12, H-2, H II, HCO+, and polycyclic aromatic hydrocarbons. LTE modeling of the CH3+ emission yields excitation temperatures of 500-800 K in the inner bubble and torus, rising to 1000-2000 K in the outer bubble of NGC 6302, with column densities ranging from similar to 10(11) to 10(13) cm(-2). This detection suggests that hydrocarbon radical chemistry must be incorporated into planetary nebulae chemical models. Further near-IR observations are crucial to map different chemical networks operating in these environments.
Author
Charmi Bhatt
Western University
Jan Cami
SETI Institute
Western University
Els Peeters
Western University
SETI Institute
Nicholas Clark
Western University
Paula Moraga Baez
Rochester Institute of Technology
Kevin Volk
Space Telescope Science Institute (STScI)
G. C. Sloan
Space Telescope Science Institute (STScI)
The University of North Carolina System
Joel H. Kastner
Rochester Institute of Technology
Harriet L. Dinerstein
University of Texas
Mikako Matsuura
Cardiff University
Bruce Balick
University of Washington
Kathleen E. Kraemer
Boston College
Olivia Jones
UK Astronomy Technology Centre
Raghvendra Sahai
California Institute of Technology (Caltech)
Isabel Aleman
Laboratorio Nacional de Astrofisica
Michael J. Barlow
University College London (UCL)
Jeronimo Bernard-Salas
CERGA (Centre d'Etudes et de Recherche de Grasse ACRI)
Innovative Common Laboratory For Space Spectroscopy (INCLASS)
Joris Blommaert
Vrije Universiteit Brussel (VUB)
Naomi Hirano
Academia Sinica
Kay Justtanont
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Patrick Kavanagh
Maynooth University
Francisca Kemper
Catalan Institution for Research and Advanced Studies
Inst Estudis Espacials Catalunya IEEC
Spanish National Research Council (CSIC)
Eric Lagadec
Observatoire de la Cote d'Azur
J. Martin Laming
Naval Research Laboratory
Frank Molster
Leidse instrumentmakers School
Hektor Monteiro
Federal University of Itajubá
Cardiff University
Anita M. S. Richards
University of Manchester
N. C. Sterling
University of West Georgia
Maryam Torki
Spanish National Research Council (CSIC)
Peter A. M. Van Hoof
Royal Observatory of Belgium
Jeremy R. Walsh
European Southern Observatory Santiago
L. B. F. M. Waters
Radboud University
Netherlands Institute for Space Research (SRON)
Roger Wesson
University College London (UCL)
Cardiff University
Finnbar Wilson
Cardiff University
Nicholas J. Wright
Keele University
Albert A. Zijlstra
Macquarie University
University of Manchester
Astrophysical Journal
0004-637X (ISSN) 1538-4357 (eISSN)
Vol. 995 1 67Subject Categories (SSIF 2025)
Astronomy, Astrophysics, and Cosmology
DOI
10.3847/1538-4357/ae1020